NextDNS Systemd-Resolved Setup Script

Overview

A comprehensive, interactive bash script for configuring NextDNS with systemd-resolved on Linux systems, featuring DNS-over-TLS encryption, automatic fallback DNS configuration, and robust backup/restore capabilities.

Features

🚀 Core Functionality

• Easy NextDNS Integration: Automatically configures systemd-resolved with your NextDNS profile
• DNS-over-TLS Encryption: All DNS queries are encrypted end-to-end
• Custom Endpoint Naming: Assign meaningful names to DNS endpoints for easy identification in logs
• Automatic IPv6 Support: Detects and configures IPv6 addresses for DNS services
• Dry-Run Mode: Test configurations without making system changes (--dry-run flag)

🔄 Fallback DNS Configuration

• Smart Auto-Detection: Automatically detects TLS hostnames, IPv6 addresses, and DNS-over-HTTP/3 support
• Service Database: Pre-configured with major DNS providers (Cloudflare, Google, Quad9, AdGuard, OpenDNS, CleanBrowsing)
• Health Checking: Tests DNS servers for responsiveness before adding them
• Multi-Protocol Support: Supports traditional DNS, DNS-over-TLS, and DNS-over-HTTP/3

💾 Backup & Restore System

• Automatic Backups: Creates timestamped backups before making changes
• User-Friendly Restoration: Interactive menu for restoring from any backup
• Multiple Backup Locations: Stores backups in both system and user directories
• Manual Backup Creation: Create backups on-demand with custom names
• Backup Management: List, restore, delete individual backups, or delete all backups

🛠️ DNS Utilities

The script adds these commands to your .bashrc:

• dns-config: View current DNS configuration
• verify-dns: Comprehensive verification and connectivity testing
• fix-dns: Fix NetworkManager DNS override issues
• dns-logs: View DNS statistics and systemd-resolved information
• dns-restore: Restore DNS configuration from backup
• dns-backup: Create manual backup of current DNS configuration
• checkdns / check-dns: Check DNS service responsiveness and protocol support
• dns-services: Show information about various DNS services

🎯 Additional Features

• NetworkManager Integration: Automatically configures NetworkManager to not interfere
• Progress Indicators: Visual progress bars for long operations
• Color-coded Output: Easy-to-read color-coded console output
• Error Handling: Comprehensive error checking and user-friendly error messages
• Root Detection: Ensures script runs with appropriate privileges

Configuration Flow

1. Backup Check: Script checks for existing backups and offers restoration options
2. NextDNS Setup: Enter your NextDNS Profile ID and optional custom endpoint name
3. Fallback DNS: Optionally add fallback DNS servers with auto-detection
4. System Configuration: Configures systemd-resolved, resolv.conf, and NetworkManager
5. Utilities Installation: Adds DNS management commands to your shell
6. Verification: Runs final checks to ensure everything is working

Supported DNS Services

The script includes a database of DNS services with their:

• IPv4 and IPv6 addresses
• TLS hostnames for DNS-over-TLS
• DNS-over-HTTP/3 endpoints
• Official websites and features

Included Services: NextDNS, Cloudflare, Google, Quad9, AdGuard, OpenDNS, CleanBrowsing

Backup System

Automatic Backups

• Created before any configuration changes
• Stored in ~/.setup-dns-backups/ (user-accessible)
• Named based on configuration (e.g., QUAD9-20240101-120000.backup)

Backup Contents

• /etc/systemd/resolved.conf
• /etc/resolv.conf
• /etc/NetworkManager/NetworkManager.conf
• ~/.bashrc

Safety Features

• No destructive actions without confirmation
• Comprehensive backups before changes
• Dry-run mode for testing
• Error checking at every step
• Automatic service restarts with verification

Requirements

• Linux with systemd and systemd-resolved
• Root/sudo privileges
• NetworkManager (optional, for NetworkManager integration)

Quick Start

Direct Download & Install

# Download the script
curl -L -o setup-dns.sh https://raw.githubusercontent.com/MPHONlC/NextDNS-Systemd-Setup-Script/main/setup-dns.sh

### Git Clone 
git clone https://github.com/MPHONlC/NextDNS-Systemd-Setup-Script.git
cd NextDNS-Systemd-Setup-Script
sudo chmod +x setup-dns.sh
sudo ./setup-dns.sh

### Dry Run (Test Mode)
sudo ./setup-dns.sh --dry-run

Manual Restore Instructions (incase the script fail to do so)

# Find where your local backups are
/home/"user"/.setup-dns-backups

# Its either named
NextDNS-YOURNEXTDNSID-202x0xxx-xxxxx0.backup

example: NextDNS-e11289-202600220-204420.backup

# Extract the contents of the .backup file, it should contain
- bashrc
- NetworkManager.conf
- resolv.conf
- resolved.conf

### Open your terminal and type (Alacrity, etc..)

sudo cp /home/"user"/.setup-dns-backups/NextDNS-YOURNEXTDNSID-202x0xxx-xxxxx0/resolved.conf /etc/systemd/resolved.conf
sudo cp /home/"user"/.setup-dns-backups/NextDNS-YOURNEXTDNSID-202x0xxx-xxxxx0/resolv.conf /etc/resolv.conf
sudo cp /home/"user"/.setup-dns-backups/NextDNS-YOURNEXTDNSID-202x0xxx-xxxxx0/NetworkManager.conf /etc/NetworkManager/NetworkManager.conf

change: NextDNS-YOURNEXTDNSID-202x0xxx-xxxxx0.backup
to the actual file name of your backup
and change "user" to your home user folder name

### you can also choose to restore your .bashrc via terminal or copy pasting it to your home directory

Support

If this project has been useful to you, consider supporting its development:

Attribution

This script is released for free public use. If you modify or distribute this script:

Please include attribution to the original author.

Example attribution in modified scripts:

# Based on NextDNS Systemd-Resolved Setup Script by [APHONlC]
# Original: https://github.com/MPHONlC/NextDNS-Systemd-Setup-Script

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Note: This script is designed for technical users. Always review scripts before running them with sudo privileges.

Note: For CachyOS and similar distro with built-in GUI to configure DNS this script is not needed. *EX: For CachyOS go to "CachyOS Hello > Apps/Tweaks > Change DNS Server" *